News Item: Ampuurna Headphone Amp (featuring Coleman Regulators) was on the Mojo Audio Stand at AXPONA 2017 - and judged Best of Show (Cost No Object).

by Steven Stone for The Absolute Sound. Read the report:
AXPONA 2017 Show Report: The Absolute Sound - Search in-page (CTRL→F) for 'best in show'.
The Ampuurna is built by Tony Landry, with EML DHTs heated with the new V7 Coleman Regulators. Good work, Tony!


Rod Coleman DHT Filament Regulator Top view

The Coleman Regulator: Filament Supply for Directly-Heated Triodes

The Coleman Regulator is a purpose-designed Regulator for heating Directly-Heated Electron Tubes. It differs from general-purpose voltage regulators in a numbers of ways:

Adding Coleman Regulators to your DHT amplifier:

"Rod Coleman" DHT Filament Regulators are available as a kit: 2x PCB + all PCB parts. Sufficient to heat 2 Tubes. You assemble the Regulator yourself, using the PCB and components.

Please add your own rectified dc (rectifiers + capacitors) - these components are not supplied.

The Regulator power transistors are cooled by mounting to a heatsink - or you can use some amplifier-chassis or metalwork for cooling.

How to buy Rod Coleman Filament Regulator Kits

To buy Coleman Regulators, Please write to: dht (at) lyrima.co.uk - I will give details concerning purchase.

Paypal Payments are accepted. I can send a PayPal invoice - it can be paid with most Cards, as well as PayPal. Price List below: given in British Pound (GBP).

Price List for Filaments <2.5A

Cost for 2 (stereo) is GBP 32 including signed delivery
Cost for 4 (2x stereo) GBP 55.50 including signed delivery
Cost for 6 (3x stereo) GBP 74.50 including signed delivery

Price List for Filaments 3.5A: GM70, 845, 211, 3C24

Cost for 2 (stereo) is GBP 33 including signed delivery
Cost for 4 (2x stereo) GBP 56 including signed delivery
Cost for 6 (3x stereo) GBP 75 including signed delivery

Price List for Filaments 4.0 .. 6.5A: RCA813, 808, SV811, Eimac 100TL, 75TL

Cost for 2 (stereo) is GBP 35 including signed delivery
Cost for 4 (2x stereo) GBP 58 including signed delivery
Cost for 6 (3x stereo) GBP 77 including signed delivery

To buy Coleman Regulators, Please write to: dht (at) lyrima.co.uk - I will give details concerning purchase.


NEW! A PCB and some parts are now available to support the raw dc supply.

Raw DC Supply Kit:

V7 PDF Technical Documents:

General Installation Manual (PDF):

Assembly Instructions (PDF):

Filament Bias - Application Note

- for 4P1L and 26 DHTs, a popular bias-method, eliminating input and cathode capacitors. Application Note (PDF):